Energy Optimization and Heat Integration in Amine-based CO₂ Capture from Natural Gas: An Aspen HYSYS Simulation Study

Abstract

The high energy demand associated with solvent regeneration remains a major limitation in amine-based carbon dioxide (CO₂) capture from natural gas, significantly affecting process efficiency and operational cost. Despite the widespread use of chemical absorption technologies, limited attention has been given to integrated energy optimization and heat recovery under region-specific conditions. This study addresses this gap by investigating energy optimization and heat integration strategies using Aspen HYSYS simulation, based on Niger Delta gas compositions. A steady-state absorber–stripper model was developed using the Electrolyte Non-Random Two-Liquid (e-NRTL) thermodynamic framework to simulate CO₂ absorption with Monoethanolamine (MEA), Diethanolamine (DEA), and Methyldiethanolamine (MDEA). Key energy indicators, including reboiler duty, condenser load, heat exchanger efficiency, and specific energy consumption, were evaluated under varying operating conditions. Heat integration strategies, particularly lean–rich heat exchange, were analyzed to minimize thermal energy requirements. Results show that regeneration energy follows the trend MEA > DEA > MDEA, with MEA exhibiting the highest energy demand. Optimized heat integration reduced overall energy consumption by 25–35%, with the greatest improvements observed in MDEA systems. Sensitivity analysis identified absorber temperature and solvent circulation rate as critical factors influencing energy demand, while efficient heat exchange enhanced thermal performance. The findings highlight the importance of balancing CO₂ removal efficiency and energy consumption. Overall, optimized MDEA systems with effective heat recovery offer a promising solution for energy-efficient and sustainable natural gas processing.